Punching tool for producing connector nail plates

ABSTRACT

A punching tool for producing, with minimum wear and maintenance of the tool, opposed prongs on a connector nail plate in which a rectangularly cross-sectioned tool has on its terminal cutting end a leading penetrating point developed from longitudinally spaced angular faces depending from a diagonal, relieved cutting edge in which angular faces merge on a transverse radius with opposed V-shaped side edges of the tool.

United States Patent Black, Jr.

[451 Aug. 22, 1972 [54] PUNCHING TOOL FOR PRODUCING CONNECTOR NAIL PLATES 2,800,961 7/1957 Cutler ..72/ 3 32 Primary Examiner-Charles W. Lanham Assistant Examiner-R. M. Rogers At t0rney-lmirie and Smiley [5 7] ABSTRACT A punching tool for producing, with minimum wear and maintenance of the tool, opposed prongs on a connector nail plate in which a rectangularly crosssectioned tool has on its terminal cutting end a leading penetrating point developed from longitudinally spaced angular faces depending from a diagonal, relieved cutting edge in which angular faces merge on a transverse radius with opposed V-shaped side edges of the tool.

10 Clains, 14 Drawing Figures PATENTEmupzz I972 FIG. 3 FIG. IB

HG. IIX

WILLIAM HILL BLACK, JF

ATTORNEY PUNCHING TOOL FOR PRODUCING CONNECTOR NAIL PLATES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to cooperating cutting tool and die sets in which a tool is driven into a sheet metal plate overlying a female die and forms a prong or nail normal to the plane of the plate.

2. Description of the Prior Art The invention concerns connector nail plates of the character disclosed in detail in US. Pat. No. 3,382,752 and more particularly to an improved ,cutting tool somewhat similar to that disclosed in US. Pat. No. 3,473,362 and in which the applicant is a co-inventor.

Tools of the character disclosed in the latter patent mentioned above, generally subject the. female die to an unusual amount of pressure since the tool actually punches the material being worked into the female die thus subjecting the female die edges to an unusual amount of pressure and wear resulting in continual maintenance and replacement, causing erratic deformaties on the nailing prongs being produced.

SUMMARY OF THE INVENTION A punching tool according to the invention comprises an angularly disposed cutting edge developed from a leading penetrating point and separating two abutment cutting faces to progressively and substantially simultaneously slice opposed a pair of connecting or nailing prongs from a flat sheet metal plate, imposing minimal wear and pressure through a progressive slicing action and producing a connector plate with uniform, regular nailing prongs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is an exploded side elevational view of punching tool and cooperating die, the latter being shown in section;

FIG. 1B is a side elevational view of the tool, looking at the side opposite that shown in FIG. 1A;

FIG. 2 is an edge elevation of the tool looking from left-to-right at FIG. 1A;

FIG. 3 is an edge elevation of the tool looking from right-to-left at FIG. 1A;

FIG. 4 is an enlarged bottom plan view of the tool;

FIG. 5 is a top plan view of the die;

FIG. 6A is an enlarged fragmentary section showing a workpiece disposed on the die, shown in section, and showing initial penetration of the leading point of the tool;

FIG. 6B is a top plan view of a workpiece illustrating the nature of the initial cut made according to FIG. 6A;

FIG. 7A is a fragmentary section, similar to FIG. 6A, showing an intermediate stage of penetration of the tool into the workpiece;

FIG. 7B is a top plan view, similar to FIG. 6B, showing the nature of the cuts made as a result of tool penetration according to FIG. 7A;

FIG. 8A is a fragmentary section, similar to FIGS. 6A and 7A, showing a pair of prongs formed in the workpiece as a result of the tool completing the cutting stroke into the die;

FIG. 8B is a top plan view of the workpiece as formed according to FIG. 8A;

FIG. 9 is a fragmentary perspective view of a connector plate produced using tools and adapted according to FIGS. 1-8B; and

FIG. 10 is a fragmentary sectional view taken substantially on the plane of line 10-10 of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawing in detail, and first considering FIGS. 1-4, a tool 10 is adopted to cooperatewith a die 12, shown in section. The tool comprises an elongated shank 14 having an upper terminal transverse head 16 for clamped receipt in a suitable tool holder (not shown). In this regard, a plurality of the subject tools may be utilized in a hydraulic ram or press, this being conventional and obvious to those skilled in the art.

The tool is ground or machined to finished dimensions and includes opposed flat or planar parallel side walls 18 and 20 and parallel side edges 22 and 24. The side edges 22 and 24 have intermediately of the shank and extending to the lower terminal end of the tool a V- shaped edge profile converging to edge profiles 26 and 28, and the faces of the side edges profiles, with respect to the flat side walls preferably are substantially 45.

The die 12, cooperative with the tool 10, comprises a body portion 30 having a slot or opening 32, with opposed flat side walls and converging end edge portions 31 and 33; see FIG. 5, for reciprocatably accommodating the lower terminal end of the tool shank and the workpiece material as illustrated in FIG. 8A, for example.

Extending diagonally between the flat side walls 18 and 20 is a cutting edge 34 which originates from a leading terminal penetrating point 36 coincident with side wall FIGS. 2 and 3. The cutting edge 34 and its leading penetrating point 36 are relieved or angled from side wall 20 to side wall 18 and comprise the forward cutting edge of a flat plane 38 which terminates in a curved portion 40 merging into the V-shaped edge profile 28.

The cutting edge 34 is coincident with a depending vertical face 42 and longitudinally spaced or below the edge 34, and relieved or angled from the base 44 of vertical face 42 is a laterally relieved, flat face 46 which terminates in a curved portion 48 merging with the other V-shaped edge profile 26. Plane 38 is at an angle of approximately 25 with respect to a transverse plane, and the face 46 is at approximately a 15 angle with respect to a transverse plane, see FIG. 1A.

Referring to FIGS. 6A and 6B, the female die 12 has juxtaposed on the upper surface 58 thereof a workpiece 60 generally comprising a sheet metal plate (galvanized or the like) preferably less than 20 gauge.

As the point 36 engages the upper surface of the workpiece 60 it moves through the material and produces a diagonal cut 62 in a shearing or slicing action, contrary to a punching or tearing action, to separate portion 64 from the plane of the plate and move it down into the die slot 32.

The downward movement of the initially sliced portion 64 of the workpiece 60 continues laterally as the tool progresses into the die slot, see FIG. 7A. Portion 64 will ultimately comprise a nailing prong or tooth having a terminal penetrating end at substantially a 45 angle, see FIGS. 9 and 10, for example. As the tool progresses into the die slot, face 38 laterally displaces portion 64, and face 46 which trails or is above face 38, ultimately depresses portion 64' into the die slot 32. It will be understood that the flat side walls 18 and 20 cooperate with corresponding sides of the die slot 32 to shear the side edges of the portions 64 and 64'. It will be further understood that portion 64' is formed with a diagonal edge 62 complementary or corresponding to the cut 62, see FIG. 7B.

Referring to FIG. 8A continued movement of the shank 14 of the tool results in profiled V-shaped side edge profiles 26 and 28 thereof cooperating with corresponding portions 31 and 33 of the die slot 32, see FIG. 8A, to ultimately displace the portions 64 and 64', respectively, substantially at right angles to the general plane of the workpiece 60 and form nailing prongs 64F and 64P at right angles to this plane.

Referring to FIGS. 9 and 10, it will be observed that nailing prongs 64P, 64'P formed in pairs, the prongs being in opposed relationship on opposite sides of a slot 66 from which they are displaced. Further, the terminal edges of these nailing teeth or prongs are oppositely angled and a transverse section will be generally V- shaped or at least concave-convex which provides a channel section of an unusual strength to the teeth.

As the connector plate 60, i.e., the prongs or teeth 64?, 64'P, are driven into a piece of wood, the prongs will tend to be cammed angularly by the angulation of their ends and grip the grain of the wood to provide an unusually uniform and desirable gripping action.

I claim:

1. A tool for producing a nail plate having a tooth unit comprising a pair of substantially parallel nails or prongs having oppositely directed angular penetrating points, said tool comprising a shank portion of rectangular section and having opposed, parallel side walls and opposed, substantially parallel edge portions, said shank portion terminating at one end in a punching and cutting portion including a first face disposed diagonally between and intermediately of said side walls and substantially longitudinally of said shank portion, a second face extending angularly of the transverse of said shank portion from one said edge portion to the extreme end of said first face and jointly defining therewith a diagonal cutting edge, said second face extending between said side walls and defining therewith lateral cutting edges, and a third face extending angularly of the transverse of said shank portion from the other said side edge portion to said first face at the inner end thereof, said third face extending between said side walls and defining therewith lateral cutting edges, the inclinations of the angles of said second and third faces being in opposite senses from said edge portions longitudinally of said shank portion to said first face.

2. A tool according to claim 1, wherein said diagonal cutting edge is disposed at an angle to the transverse of said shank portion and defines with one said side wall a piercing point.

3. A tool according to claim 2 wherein said shank edge portions are relieved relative to said side walls at said punching and cutting portion. 9

4. A tool according to claim 3 in combination with a die having a slot to receive said tool and having parallel side alls enable a s can g action by said ateral cutting e ges, said slot having edge portions corresponding in configuration with and complimentary to said tool edge portions and spaced to accommodate the thickness of said plate between each said tool and slot edge portions to produce nail prongs of channel section.

5. A tool according to claim 4 wherein said second and third faces are planar and perpendicular to said side walls, the outer ends of said faces being curved and merging with the respective edge portions to bend without weakening the roots of the nail prongs into said die slot.

6. A tool according to claim 5 wherein said edge portions have V-shaped profiles.

7. A tool according to claim 3 wherein said first face is disposed at approximately 45 to the planes of said side walls.

8. A tool according to claim 7 wherein said second and third faces are planar and perpendicular to said side walls, the outer edges of said faces being curved and merging with the respective edge portions to bend without weakening the roots of the nail prongs.

9. A tool according to claim 8 wherein said second face is disposed at substantially 25 to the transverse of said shank portion.

10. A tool according to claim 9 wherein said third face is disposed at substantially 15 to the transverse of said shank portion.

Eavin a close fit with said tool side wags to 

1. A tool for producing a nail plate having a tooth unit comprising a pair of substantially parallel nails or prongs having oppositely directed angular penetrating points, said tool comprising a shank portion of rectangular section and having opposed, parallel side walls and opposed, substantially parallel edge portions, said shank portion terminating at one end in a punching and cutting portion including a first face disposed diagonally between and intermediately of said side walls and substantially longitudinally of said shank portion, a second face extending angularly of the transverse of said shank portion from one said edge portion to the extreme end of said first face and jointly defining therewith a diagonal cutting edge, said second face extending between said side walls and defining therewith lateral cutting edges, and a third face extending angularly of the transverse of said shank portion from the other said side edge portion to said first face at the inner end thereof, said third face extending between said side walls and defining therewith lateral cutting edges, the inclinations of the angles of said second and third faces being in opposite senses from said edge portions longitudinally of said shank portion to said first face.
 2. A tool according to claim 1, wherein said diagonal cutting edge is disposed at an angle to the transverse of said shank portion and defines with one said side wall a piercing point.
 3. A tool according to claim 2 wherein said shank edge portions are relieved relative to said side walls at said punching and cutting portion.
 4. A tool according to claim 3 in combination with a die having a slot to receive said tool and having parallel side walls having a close fit with said tool side walls to enable a shearing action by said lateral cutting edges, said slot having edge portions corresponding in configuration with and complimentary to said tool edge portions and spaced to accommodate the thickness of said plate between each said tool and slot edge portions to produce nail prongs of channel section.
 5. A tool according to claim 4 wherein said second and third faces are planar and perpendicular to said side walls, the outer ends of said faces being curved and merging with the respective edge portions to bend without weakening the roots of the nail prongs into said die slot.
 6. A tool according to claim 5 wherein said edge portions have V-shaped profiles.
 7. A tool according to claim 3 wherein said first face is disposed at approximately 45* to the planes of said side walls.
 8. A tool according to claim 7 wherein said second and third faces are planar and perpendicular to said side walls, the outer edges of said faces being curved and merging with the respective edge portions to bend without weakening the roots of the nail prongs.
 9. A tool according to claim 8 wherein said second face is disposed at substantially 25* to the transverse of said shank portion.
 10. A tool according to claim 9 wherein said third face is disposed at substantially 15* to the transverse of said shank portion. 